501 Squadron was one of the most heavily engaged units in RAF Fighter Command and won seven battle honours flying Spitfire, Hurricane and Tempest fighter aircraft during WW2. The squadron saw extensive action during the Battle of Britain, with 19 pilots killed, more than any other squadron.
ROYAL AIR FORCE FIGHTER COMMAND, 1939-1945. (CH 2826) Three Supermarine Spitfire Mark Is of No 501 Squadron RAF based at Colerne, Wiltshire, flying in line astern. Copyright: © IWM. Original Source: http://www.iwm.org.uk/collections/item/object/205210069